For Summer
by Be3
Summary: In which Hermione Granger casts the Patronus Charm with surprising success, even though it would not have worked against a Dementor. A one-shot spin-off the HP and the Methods of Rationality, Chapter 88. Wild speculations abound.


A/N: this is a what-if based on the events of Chapter 88 of the marvelous fic Harry Potter and the Methods of Rationality, so the rights belong to JK Rowling and LessWrong, respectively.

There are SPOILERS for that chapter, if you haven't guessed.

…okay, shoot me, I had to write this.

* * *

When Harry's Patronus left Hermione's side, she was already informed of the situation.

She was already running from a very big, very ugly mountain troll down a deserted corridor.

Already winded, but not yet panicking.

Because there was help coming, and she only had to keep ahead of the troll – why, she could fly away if she so wished.

She snorted, because really, how do you get Hermione Granger on a broom if not by sending a monster after her.

_and they had to talk about his Patronus sometime soon_

But the broom failed her.

And everything else, which she could spare breathe to take out of her bag, failed her, too.

And Hogwarts was so unbelievably, ridiculously empty.

And bright daylight poured in through high, narrow windows on one side.

It was then that fear burst in her.

_faster_

Because back in September, playing at being a Scientist, Hermione wondered why the third most perfect killing machine in all of Nature could be frozen by something as mundane as a ray of a totally non-magical star. (No, Mr. Potter, I don't have proof!)

As to why the ray shouldn't have been reflected by the Moon or any other planet before hitting the target, well, that was another question.

And she had been proud of actually thinking of that.

_need air_

_slow down _

_no time _

Why does a non-magical something influence a magical something? And not in Potions making, which seldom used living things and never – sapient ones? (To her knowledge). She resolved to answer that one when she graduated.

_never_

Okay, speculated then Professor Granger, maybe trolls hadn't been so vulnerable from the start, but a powerful Mage cursed their whole breed – not a smart one, but certainly powerful; though maybe that was the best he could do.

_correction_

_maybe he was Bad and designed trolls for night-time attacks_

_maybe he was _really_ Bad and that was the best he could do_

_and someone made improvements_

_just for her?_

_or were all trolls now sun-proof?_

_stumble_

_wall_

_skinned knees_

_go_

She had meant to discuss it with Harry. There was little info in the library. Harry was busy. There was homework!

And she had told herself that magic didn't make sense.

Hermione felt her legs folding beneath her, threw out an arm not to slam into another wall and almost broke her fingers; her eyes watered from pain.

And the predator behind her grew nearer.

_but not yet just behind_

'What..'

She raised her head as if out of water – sweat running down her burning face – and saw a picture of a wizard surrounded by geese as tall as himself.

'Help,' Hermione wheezed out. The wizard blinked myopically. She pushed away with a gasp, and soon – too soon – heard the club crash into the stone.

So the picture was smashed.

And she was still running.

_why?_

This was a mountain troll, and it hadn't trampled her into the floor in seconds?

Hope flared briefly, but she was a General and it was clear, it was _clear_ that –

_it was herding her_

_something more terrible was waiting out there  
_

Hermione hurled her bag over her shoulder.

_think_

_open air?_

_no_

_where?_

_here_

She dove sideways, into a narrow cul-de-sac, through blinding stripes of powerless sunlight, skidded, fell into an alcove. Mistake. Her movements were restricted, and there was zero protection from –

The troll turned the corner.

Idly lifted its weapon.

Advanced a step, crossing a harmless band of light from a high, narrow window. It was like some special effect in a Muggle movie.

_where was Harry?_

'Incendio!'

Missed.

'INCENDIO!'

Missed. It moved so quickly!

'Glisseo!'

Wasn't even noticed.

'Somnium!'

_What?_

_Well it does have a brain!_

Another step. It was toying with her.

_think_

She couldn't cast the Killing Curse.

This thing was impervious to the usual means.

Nobody was coming to help.

Harry didn't know the _details_.

She couldn't flee.

_think_

Another step.

Why did the Sun work? Why didn't the Sun work now?

Let it be solvable. Please. Let the troll be enchanted.

'FINITE INCANTATEM!'

It held out a hand, tenderly cupping the bright beam in its palm.

_Her_ hands were cold. She was… crying?

_think!_

Harry made weapons from everything. When he wanted a sword, he made a sword.

Useless – the troll maintained constant Transfiguration on itself. It could only be defeated in one piece.

So? Apply energy, like Harry did that time with photosynthesis.

Useless – no source of energy, and nothing could penetrate its armour.

_because stone didn't_

_conduct light_

_in most cases_

Feeling nothing much, she raised her wand and twitched it once, twice, thrice and four times, and her raw fingers moved as if of their own will.

Harry believed she could do it.

There was no reason why she couldn't do it. Aside from hiccuping.

The troll leaned forward.

_Mom, I will be home for summer_

She whispered the words.

And won.


End file.
